1. Technical Field
This invention relates to a hydrophilic polyorganosiloxane composition which cures into an elastomeric or gel-like product, that is, cured silicone rubber or cured silicone gel.
2. Background Art
Polyorganosiloxane compositions currently find widespread use in building, electric/electronic and dental applications. Due to the siloxane's own property of water repellence, these compositions suffer from problems. In the building application, it is difficult to apply aqueous paint to the surface of material. In the dental application, the composition is useful as dental impression material, but difficult to take a precise impression.
The above problems are conventionally remedied in the building application by adding a hydrophilic filler such as calcium carbonate and in the dental application by adding polyether. Such solutions are unsatisfactory in either application partially because the base is polydimethylsiloxane. The mere addition of filler allows for variant coatings of aqueous paint. On the internal addition of polyether, the polyether will separate from the composition in the uncured or cured state with the passage of time, resulting in variations of impression.
JP-B 6-37558 corresponding to U.S. Pat. No. 4,877,854 discloses a curable composition comprising an allyl-terminated polyether as a base polymer and a polyether-modified organohydrogenpolysiloxane as a crosslinking agent. This crosslinking agent is difficult to synthesize. Still worse, the curing property declines with time as the allyl groups at base polymer ends undergo internal rearrangement by the oxidizing action of platinum catalyst.